Fig 1.
(A) SEM Microscopy SEM 10000x 15 kV FTO-GLAS Clean, FTO-GLASS EDX Analysis (B) Microscopy SEM 10000x 15 kV FTO-GLAS-APTES with their respective diffraction in FTO- GLAS-APTES; (C). Microscopy SEM 10000x 15 kV FTO-GLASS-APTES-PDITC and Diffraction; (D). Microscopy SEM 10000x 15 kV FTO-GLAS-APTES-PDITC-DNA and diffraction.
Fig 2.
Raman shift of interaction with each monolayer; FTO-nude, this the first step for modification of the sensor, followed by monolayers of APTES, PDITC and DNA, showing an interaction between them demonstrating adequate coupling.
Fig 3.
(A) Voltagrams of each stage of immobilization in an electrochemical cell with a three-electrode configuration; Reference electrode (Ag / AgCl 1.0 M), Counter-electrode (Platinum), Working electrode (FTO-MODIFIED) Ferri / Ferro 0.1 M in Buffer PBS 0.1 M, in a potential window -0.400 to 1.100 V, at a rate of 100 mV/s. (B) Voltagrams of the different scanning rates using the FTO-DNA capture electrode, ranging from 10 mV/s to 250 mV/s.
Fig 4.
Sensor response represented by the behavior of the absolute value of the cathodic peaks towards samples without synthetic DNA (BLANK), samples with 50nM of non-complementary synthetic DNA sequence and samples with 50nM of complementary synthetic DNA sequence.
Fig 5.
Sensor calibration curve using the absolute value of cathodic current peak versus target DNA concentration in a range 1 nM to 500 nM, showing a logarithmic trend.
Fig 6.
Sensor calibration curve using the absolute value of cathodic current peak versus target DNA concentration in range 1nM to 100nM, showing a lineal trend.
Fig 7.
(A) Ratio of the sample signal (DNA) divided by the baseline signal (EA) of the concentrations, 160 ng/mL (2.00x10-2), 0.016 ng/mL (2.00x10-6), 0.00016 ng/mL (2.00x10-8) and 0. 0.000016 ng/mL (2.00x10-9). (B) 12% acrylamide gel of the PCR amplicons at dilutions 1 (2.00x10-2), 2 (2.00x10-6), 3 (2.00x10-8) and 4 (2.00x10-9).
Fig 8.
(A) Three "Spikes" urines were evaluated containing 100 ng, 1 ng, 10 pg, 100 fg and 1 fg of MTB DNA. It was compared with real time PCR.
Fig 9.
The response ratio of the sputum samples according to the bacillary load presented in the sputum smear (BK).